Water tube boiler



Dec. 20, 1932. YARRQW 1,891,862

WATER TUBE BOILER Filed Sept. 28. 1931 INVENTOR HayE Yarrow BY ATTORNEY Patented Dec. 20, 1932 UNITED STATES HAROLD EDGAR YARROW, OF GLASGOW, SCOTLAND WATER TUBE BOILER Application filed. September 28, 1931, Serial No.

This invention relates to water tube boilers of the Yarrow type in which there are on at least one side of the combustion space two water drums connected with an elevated steam drum by banks of steam generating tubes, a superheater being usually disposed in the space between these two banks of tubes.

The upper or outer bank of steam generating tubes is very considerably extended in length compared with the inner or lower bank and is provided with transverse battles, so that the gases pass acrossthe tubes two or more times before passing to any accessory heating device.

According to the present invention there is provided underneath the upper or outer bank of steam generating tubes a large soot hopper which extends over a considerable part of the length of the tubes, and as the tube rows are comparatively few in number for a given surface owing to the tubes themselves being longer, cleaning is facilitated and by means of the hopper flue dust is automatically deposited in a place from which it can readily be removed. The length of the tubes in the upper or outer bank is preferably about a third as long again as the tubes of the other bank, so as to permit of the employment of two transverse baflles resulting'in three passes of the furnace gases across the tubes.

Another advantage of the arrangement is that owing to the gases traversing the upper bank of tubes several times, a maximum amount of heat is absorbed by these tubes by convection, and this is of great importance when the temperature of the gases has been considerably reduced, as by traversing a 40 superheater interposed between the two banks of steam generating tubes.

One embodiment of the invention is illus trated in the accompanying drawing as applied to a Yarrow boiler of the single flow type, but it will be understood that the invention can also be applied to a Yarrow boiler of the double flow type in which the furnace gases pass upwardly around both sides of the saturated steam drum.

50. In the drawing, which is a transverse sec- 565,592, and in Great Britain November 4, 1930.

tion of a com lete boiler system, the furnace is shown as died by means of a mechanical stoker A having at either side water boxes B connected by tubes B with the saturated steam drum G. The front water drum C, back water drum D and upper or outer water drum F are respectively connected by steam generating tubes C, D, F with the saturated steam drum G. The tubes F are made considerably longer than the tubes C, D, and are provided with baflles H, J which constrain the furnace gases, after traversing the tubes D, to traverse the tubes F in three transverse passes before passing to a flue K leading to an economizer L, after which they traverse an air preheater M on their way to the uptake or induced draught fan.

lVhen, as shown, there is a superheater indicated at E interposed between the tubes D and F, it will be understood that the latter tubes can be of any reasonable length, since they work at a low rate of steaming owing to the gas temperature being considerably reduced by the time the gases leave the superheater. When the tubes F are so extended it becomes possible to have quite a long soot hopper P underneath these tubes and, as shown in the drawing, this soot hopper extends under the second and third passes of the tubes F and enables flue dust to be automatically deposited in a place from which it can be readily removed.

It will be understood that any suitable means may be provided for varying the degree of superheat by by-passing some of the furnace gases directly from the tubes D to the tubes F without traversing the superheater tubes.

Having thus described the nature of the said invention and the best means I know of carrying the same into practical effect, I

the said inner bank of tubes, battles for the 10 outer bank, said bafiies being constructed and arranged to compel the gases to traverse said outer bank of tubes in several passes, and a soot hopper arranged beneath said outer bank over a considerable portion of its length.

2. A water tube boiler of the Yarrow type, comprising an elevated steam and water drum, two water drums on one side of the furnace, two banks of water tubes, namely an outer bank and an inner bank, connecting the respective water drums with the saturated steam drum, said outer bank being of considerably greater length than said inner bank of water tubes, a steam superheater located between the said two banks of tubes, battles for the said outer bank constructed and arrangedto compel the gases'to traverse said outer bank of tubes in several transverse passes, and a soot hopper arranged beneath said outer bank over a considerable portion of its length.

31A water tube boiler of the Yarrow type, comprising an elevated steam and water drum, two water drums on one side of the furnace, two banks of water tubes, namely an outer bank and an inner bank, connecting the respective water'drums with the saturated steam drum, said outer bank being of considerably greater length than said inner bank of water tubes, avsteam superheater located between the said two banks of tubes, baflles for the said outer bank constructed and arranged to compel the gases'to traverse said outer bank oftubes in several transverse passes, a soot hopper arranged beneath said outer bank over a considerable portion of its length, and an economizer disposed on the farther sideof the outer bank of tubes in the direction of travel of the furnace gases.

- 4.- A water tube boiler of the Yarrow type, comprising an. elevated steam and: water drum, two Water drums on one sideor the furnace, two banks of water tubes, namely an outer bank and aninner bank, connecting the respective water drums with the saturated steam drum, said outer bankbeing of considerably greater length than said inner bank of Water tubes, a steam superheater located between the said two banks of tubes, bafiies for the said outer bank constructed and arranged to compel the" gases to traverse saidouter bank of tubes in several transverse passes, a soot hopper arranged beneath said outer bank over a considerable portion' of its length, an economizer disposed on the farther side of the outer bank of tubesin the direction of travel of the furnace gases, and an air preheater disposed on the farther side of the saideconomizer in the direction of travel of the furnace gases.

5. A watertube boiler of the'YarroW type, comprising an elevated steam and water drum, two water drums on one side of the furnace',.two banks-of water tubes, namely an outerbank and an inner bank, connecting the respective water drums with the saturated steam drum, said outer bank being of considerably greater length than said inner bank of water tubes, a steam superheater located between the said two banks of tubes, baflles for the said outer bank constructed and arranged to compel the gases to traverse said outer. bank of tubes in several transverse passes, a soot hopper arranged beneath said outer bank over a considerable portion of its length, a mechanical stoker located in the boiler furnace at a lower level than the said water drums, water boxes at each side of said mechanical stoker, and water tubes connecting said water boxes with the steam and water drum. I w g V In testimony whereof I have signed my name to this specification.

HAROLD EDGAR YARROW. 

